1. Field of the Invention
The present invention relates to a disk drive with a tray, which sets a disk thereon and can be taken out and in from a drive body.
2. Related Art
Generally, many disk drives comprise a tray, and a disk is carried in and out of a drive body by the tray. That is, a disk is set on a tray projecting from a drive body to be carried into the drive body to be placed on a turntable of a traverse unit, and conversely a disk having been placed on the turntable is transferred onto the tray to be carried out.
FIG. 6 shows a conventional disk drive in a state, in which a tray 1 is carried out and put in a disk exchange position. The tray 1 is formed on a top thereof with a circular-shaped, shallow recess, and a disk is fitted into the recess to be set. Provided on a back surface side are a rack 2 extending longitudinally and a substantially L-shaped guide groove 3 along the rack 2. A gear 4 meshes with the rack 2 and a boss 5 projecting from a rack loading device 10 is loosely fitted into the guide groove 3.
The gear 4 is driven by a motor 6 to rotate, and upon rotation of the gear 4, the rack 2 and the tray 1 retreat to be carried into the drive. The tray 1 advances and retreats a predetermined distance to be opened and dosed, and the substantially L-shaped guide groove 3 comprises a longitudinal guide groove 7 in parallel to the rack 2, a transverse guide groove 8 perpendicular to the rack 2, and a corner guide groove 9 connecting obliquely between the longitudinal guide groove 7 and the transverse guide groove 8. Also, a rear end of the longitudinal guide groove 7 extends via a curved portion 7a. 
In the case where the tray 1 is carried out to advance and move to a disk exchange position, when the boss 5 loosely fitted into the longitudinal guide groove 7 comes to the curved portion 7a, movement of the rack loading device 10 is detected and the tray 1 is stopped. In the case where the tray 1 is carried in to retreat and move to a disk reproduction position, when the boss 5 loosely fitted into the longitudinal guide groove 7 comes to the corner guide groove 9, the rack loading device 10 is likewise moved and the tray 1 is stopped. That is, movement of the boss 5 along the guide groove 3 results in movement of the rack loading device 10 being a body of the boss, and the tray 1 is stopped upon detecting the movement.
JP-A-2003-100004 discloses “Disk recording/reproducing device equipped with tray retractably” that comprises a positioning mechanism preventing inadvertent lateral movement of a slide body, which includes a projecting wall having a first wall provided on an underside of the fray to extend longitudinally and a second wall extending contiguous and perpendicular to the first wall, and at least two projections provided on the slide body to interpose therebetween the second wall in a state, in which the tray has completed advancement, and interpose therebetween the first wall in a state, in which the tray advances or retreats”.
In this manner, a construction, in which two rods interpose a continuous wall extending longitudinally instead of a guide groove, is small in an area occupied by constituent parts of a positioning mechanism for a rack loading device, as compared with the case where the boss 5 protrusively provided on the rack loading device is loosely fitted into the guide groove. Also, the provision of two projections (bosses) enhances strength and prevents the projections from breaking even upon application of a shock.
With such conventional construction, however, an external shock in some cases releases the gear and the rack from meshing with each other to make carrying-in and out of a tray impossible. Also, there is caused a problem that because of driving in a state, in which a tip of the gear meshes, the tip can break.
Further, in the case where two projections interpose therebetween a wall serving as a guide as in the disk drive disclosed in JP-A2003-100004, interfacial friction on the wall increases and a moment is generated based on the frictional resistance to tend to change a direction, in which a tray slides. Accordingly, while the tray slides while being guided, it is hard to guarantee a smooth slide. Further, a thin L-shaped wall is lowered in functioning as a reinforcement rib for the tray, as compared with the guide groove 3.